Transmission and reception of pictures



, March 10, 1931. R. D. KELL TRANSMISSION AND RECEPTION OF PICTURES Filed April 25, 1929 Fig.1,

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Patented Mar. 10, 1931 I UNITED STATES PATENT OFFICE m! n. KELL, or scorn, NEW YORK, assrenon ro GENERAL mimic 001mm,;

' v coaronarron or NEW YORK TRANSMISSION AND RECEPTION 01 PICTURES Application filed April 25, 1929. Serial No. 858,078.

My invention relates to the transmission ference between the successive images of a and reception of pictures, and has for its picture or moving object. principal object the provision of an im roved The picture transmitting apparatus of Fig. ap aratus and method of operation w ereby 1 includes a light source from which a 8 on y the difference between the successive beam of light is projected through a lense 11, 55 images of the picture or object is transmitted a scanning member 12 and a lens 13 upon a and received. 3 field of view including the object 14, the image Various types of picture transmitting apof which is to be transmitted. The scanning paratus including either a radio transmitter disk 12 is provided with a plurality of 1 and receiver or a transmitter and receiver inspirally arranged perforations 15 and with so terconnected by electrical conductors have suitable driving means such as a motor 7, been provided in the past. Many of these When this motor is rotated, the beam of apparatus involve the use of both means for 'llght is utilized in a well known manner to producing light dependent on the shade of scan the field of view containing the object 15 successive elemental areas of the picture to 14 and light of an intensity dependent on 05 be transmitted and means for converting such he Shade f the S ccessive element-a1 areas light into electrical impulses which must be of the field containing the object is reflected reconverted into light at the picture receiv-' h r r m- 1 ing station. This reflected light is received by one or It has been customary in the past to transmore light sensitive cells 16 which convert mit successive complete images of the transthe llght into electrlcal im ulses of an inmitted picture. This method of pi tur tens ty dependent on the s ads of the suctransmission requires a band of frequencies 08851179 ent ar of the picture. These dependent on the number of picture elements c r qal imp lses are apphed to a radio 25 and the number of images transmitted "per transmitter 17 through an amplifier l8 and v second. Since only a limited band of frea rm r 19, a phase shifting device 20 quencies are available for picture transmisof any fihle type, Such as that disclosed sion. the fineness in the detailof the transby the Un1ted States patent of E. mitted picture has therefore been determined e n n N 1,655,037 being connected 8 b th number f i t l t d th between the ampllfier 18 and the transformer so number of pictures transmitted per second. 19 for he purpose of prevent1ng the trans- In a co dan 'with my inv nti thi diflimission of electrical impulses between the culty is avoided by transmitting only the dif- P and the lfldle transmitter When ference between the successve images of the there has been 'Q change 111 the P 1 1 r 35 object. By this mode of operation, no signal Shadmg 9 the P is transmitted when there is no change in the c T Phase shlfimg tune f y devlce image of the picture or Object and its fineness 20 is connected between the amplifier 18 and one section 21 of the primary winding of the gi gjg g i g t g ggg the speed of the transformer 19. The other section 22 of this 40 primary winding is connected directly to the My mventmn W111 be better understood amplifier 18. With these connections, the

ft'om the following description when primary winding sections 21 and 22 are subsldered in connection with the accompanying jected to the Same electrical im ulses the drawmgs and Its Scope W111 be Pomted out m phase of these impulses being shiited before 45 the appended claimsthey are a lied to the winding section 21.

i r g to h l i 1 lnusimtes The eleiit i'ical impulses corresponding to ap u translmttmg PR Where/111 y the shade of the successive elemental areas of lnv n n has e n emhedled; and F g 2 t0 the field of view are thus applied to the wind-.

5 lllustrate various details of an apparatus ing section 22 at one time and to the winding 60 which may be utilized to receive the dif-- section 21 at a subsequent time. The time winding section 21 at the same time that the winding section 22 is being subjected to the electrical impulse produced by the next subsequent scanning of this elemental area. The connection between the device 20 and the winding section 21 is such that-the original the delayed impulses produce opposing e acts in the transformer. Under these conditions, the'electrical impulses cancel one another when the shade of the given elemental area has not changed between successive scannings, and no si al is ap' lied to the radio transmitter. en the s ade of the elemental area changes,'however, the

impulses applied to the different winding sections.- are unequal and a si a1 corresponding to the change in sha e is transmitted.

Under these conditions, a complete image of the object 14 is transmitted when it is first completely scanned and thereafter only the differencebetween successive images of the object is transmitted. Thus if there is no movement or change in the shading of the object 14, no impulses are transmitted by the transmitter 17 after the first complete scannin of the object; if'the object moves only slig tly so that there is a change in shade of certain elemental areas only of the field of view, electrical impulses. due only to the change in shade of those areas are transmitted; and if the object changes to an entirely new position impulses corresponding to the image of the entire object are transmitted.

Any suitable apparatus may be utilized to receive the transmitted electrical impulses and to produce an image which is shaded in accordance with these impulses. One such apparatus is disclosed in a copending application of Augusto Bissiri, Serial N 0. 244,531, filed Jan. 4, 1928, and assigned to the same present application. apparatus includes a screen which is illuminated from the side and is provided with a plurality of elements arranged to be moved into the range of. illumination to an extent determined by the intensity of the received electrical impulses.

Figs. 2 to 5 illustrate a screen 23 which is arranged to be illuminated by suitable light sources (not shown) mounted near its periphery and ,which is provided with a plurality of movable devices 25 and 26 are provided with contact members 27 and 28 which are connected to a radio receiver 29 and are mechanically cougiven 1,7ae,oso

gears 30 to 33 for the purpose of maintaining a definite relation between their speeds of rotation. Power for drivin the contact devices suitab e means such as a motor 34 mounted on the same shaft as the gear 32 and operated at a speed which bears a predetermined relation to the sp he scanning disk 12 pled together through of the transmitting apparatus. Each of the squares in the screen 23. represents one of a plurality of elemental surfaces which are controlled by the commutators 27 and 28, and

I may be moved in a direction perpendicular to the screen surface for the purpose of varying the amount of light reflected from them. The actual construction of the screen is illustrated by Figs. 2, 3 and 5.

is supplied by As indicated by these figures each elemental portion 24 of the screen may be made in the form of a pyramid, a cone or the like be supported on pivoted members 35 and arranged to be moved transversely to the surface of the screen by means of 'electro-responsive devices 36 which are energized in accordance with the current transmitted to them through the radio receiver 29 and the commutators 27 and 28.

varies in accordance with the shading of the is current of course picture to be produced, and it will be readily understood that when the picture transmitting and receiving apparatus are roperly synchronized, the magnitude of t e currents supplied to the electro-responsive devices 36 controlling the various elemental portions 24 of the receiving screen 23 will be dependent on the shading of the corres 0nding elemental portions of the object, the image of which is to be transmitted. Under these conditions the position of each elemental rtion 24 of the screen and the amount oflight which each of these portions receives and reflects, is dependent on the shading of a corresponding elemental portion of the object.

The rapidity with which the electrical connections are changed from one to another of the electro-responsive devices 36 is dependent on the rotational speed of the driving motor 34 and ordinarily does not need to be faster than that required to complete the connections of all the electro-responsive devices more than once every ond. Thus assuming for example, that the screen 23 is square and contains 100 elemental surface portions, the commutator 28 should e driven at a speed of 160 revolutions per second and the commutator 25 should be driven at a speed of 1600 revolutions per second. Each of the elemental screen is gripped by a spring 39 when the electroresponsive elements 36 are deenergized.

Each of the electro-responsive devices 36 one-sixteenth of a sec-' screen element and the-coil 38 being arranged on the intensity of the electrical impulse applied to the coils. At'the termination of eachv electrical impulse, the elemental screen section is gripped by the spring 39 and its position does not change until its electro-responsive device 36 is subjected to another impulse. Under these conditions the first complete scanning of the object causes the elemental screen sections 24 to assume positions dependent on the shade of the successive elemental areas of object. Thereafter no change in the position of the screen sections is produced unless the osition or shadin of the object is changed: When the position or shading of any part of the object changes, signals are transmitted and the corresponding elemental sections of the receiving screen are moved to positions dependent on the intensity I of the impulses received by the electro-responan sive devices 36.

the screen except the elemental surfaces are black; that these surfaces are white and that as the screen is continuously illuminated in a plane arallel with its surface. Under these conditions the illumination and visibility of the image produced is altogether dependenton the position of the various elemental surfaces, these positions being determined by the shading of the object and being changed in accordance with the change in shading, which results from movement of the object. It will be apparent to those skilled in the art that the advantages of transmitting only the difference between the successive images of the object are not limited to the particular type of receiving apparatus illustrated and described but may be realized in connection with any suitable type of receiving apparatus.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A picture producing apparatus including means for scanning a field of view including a movable object, means arranged to generate electrical impulses dependent on the shade of the successive elemental areas of said field, and means 0 erable after the first complete scanning 0 said field to permit the transmission of only the electrical impulses corresponding to those elemental areas of said 'field, whichhave'changed shade subsequently to the previous scanning.

2. A picture producing apparatus includ- 65 ing means for scanning a field of view inare indicated. It will be observed cluding a movableobje'ct, means arranged to generate electrical impulses dependent on the shade of the successive elemental areas of said field, and phase control means operable after the first complete scanning of said field to permit the transmission of only the electrical impulses corres onding to the elemental areas of said fiel which have changed in shade subsequently tq the previous scannm g 3. The method of icture transmission which includes roducmg an efiect dependent-on the sha e of all the successive elemental areas in a field of view including an object, and subsequentl producing an effect dependent on the sha e of those elemental areas only in said field whose shade has changed subsequently to the production of the first eflect. a

4. The method of producing a picture of a moving object at a distant point which in-' cludes transmitting electrical impulses dependent on the shade of all the successive elemental areas in a field of view including said object,andsubsequentl transmitting impulses from those elementa areas only whose shade has changed subsequently to the first transmission.

5. A picture producing a paratus including means for scanning a eld of view including a movable object, means arranged to the shade of the successive elemental areas of said field, and phase control-means arranged to cause neutralization of the electrical im ulses which correspond to the shade of the e emental areas of said field whose shade remains unchanged.

6. Picture transmittlng apparatus comprising means for successively scanning a eld of view, means for generating electrical impulses dependent upon the shade of the seccessive elemental areas covered by the scanning means, means for producing from said impulses other impulses having a time delay equal to the intervals between the sucgenerate electrical impulses dependent on cessive scannings, combining means arranged to cause the originaland the delayed 1mpulses to oppose each other, and transmitting means responsive to the resultant impulses.

7. Picture transmitting apparatus comprising means for succesively scanning a field of view, means for generating electrical impulses dependent upon the shade of the sucdelay device, said. primaries being arranged in op sition, and transmittin means connectef with the secondary 0 said transformer. 5 In witness whereof, I have hereunto set my hand this 24th day of A ril, 1929.

RXY D. KELL. 

